1. Field of the Invention
The present invention refers to a vertical coil winder suitable to wind a hot rolled material, as for instance metallic wires.
A coil winder for said use is, for instance, described in the Italian patent no. 673654.
2. Discussion of the Background
The skilled in the art know very well coil winders comprising a reel which has a structure formed by a cylindrical container, the so called "basket", inside which a plurality of vertical rods, positioned along a circumference, is provided.
A gap is therefore formed between the outer wall of the cylindrical container and said rods, wherein the metallic wire (or other hot rolled products), coming from the upstream roll mill, is placed and wound thanks to the rotation of the reel.
For obvious productivity reasons, the need to provide heavier coils, and, as a consequence, taller coils is more and more felt.
However, such a need increases the already existing problems in extracting easily and without problems the coil from the reel.
The problems in extracting the coil from the reel are mostly related to the progressive cooling of the hot material during the winding operation, said cooling causes a decrease in the length of said material, thus causing the tight locking of said material on the rods of the reel.
This is the fact that causes the problems in extracting the coil, additionally, said extracting operation has to be done right after the completion of the winding operation in order not to worsen the problems created by the progressive cooling of the material.
In order to overcome this problem, it has already been proposed to manufacture coil winders, provided with rods converging towards the upper portion of the reel, i.e. towards the inlet side of the hot rolled material, said side is also the side wherefrom the finished coil is extracted.
However, this proposal has not produced fully satisfactory results, since the slant of the rods cannot go beyond a certain angle, to avoid to obtain internally conical coils (i.e. with coils having a decreasing diameter going from the bottom to the top) not always acceptable on the market. As a consequence, even the use of converging rods has not satisfactorily solved said problem, since said use did neither eliminate the significant forces needed to separate the coil from the rods nor the internally conical coils.
In addition, even in this case, if for production or accidental reasons, the coil extracting operation cannot be performed immediately after the completion of the winding operation of the hot product, the coil undergoes a further cooling thus developing such forces that unusual means (as for instance a crane) shall be required to extract the coil from the reel.